Process of making battery-anodes



F- FRENCH.

PROCESS OF MAKING BATTERY ANODES. APPLICATION FILED 05c. 27, 1915.

1,359,244. Patented NOV.

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INVENTOR, HARRY 1". TBBNBH A TTORNE Y UNITED STATES PATENT OFFICE.

HARRY F. FRENCH, OF FREMONT, OHIO, ASS-IGNOR, BY MESNE ASSIGNMENTS, TO NATIONAL CARBON COMPANY. INC., A CORPORATION OF NEW YORK.

PROCESS OF MAKING BATTERY-ANODES.

Patented Nov. 16, 1920.

Application filed December 27, 1915. Serial No. 68,605.

To all whom it may concern:

Be it known that I, HARRY F. FRENCH, a citizen of the United States, residing at Fremont, in the county of Sandusky and State of Ohio, have invented a certain new and useful Improvement in Processes of Making Battery-Anodes, of which the following is a full, clear, and exact description.

My invention relates to electric batteries employing zinc as the positive electrode, and while not necessarily restricted thereto, the invention is particularly applicable to batteries with alkaline electrolyte.

It has been the practice in the past to construct primary alkaline batteries with copper oxid depolarizer, with either rolled or cast zinc as the positive electrode. Cast zinc seems to have some advantages over rolled zinc, which is probably due to its crystalline structure, but I have found that both are inferior to specially cast zinc, which is the subject of this invention.

Zinc electrodes as ordinarily cast are cooled quickly by the relatively cold mold and have small crystals arranged in such a way that they all point inward from the sides and edges. This structure of the zinc may be plainly seen by breaking a zinc castmg.

I have found that if the zinc casting is cooled slowly it changes its structure entirely and consistsof large crystals arranged in such a way that its fracture has the appearance of superposed layers or flakes of zirgrparticles extending across the plate.

' en a zinc casting, as ordinarily cast, is subjected to suflicient stress to break it, it breaks very suddenly, as it is quite brittle. However, with the slowly cooled zinc castmg, the zinc is not brittle, but will bend considerably without breaking, when subjected to sufficient bending stress. Also the bending of the specially cast zinc produces a cry resembling the noise emitted by a rod of lead or s'older when bent suddenly.

Referring to the drawing, in which like numerals of reference designate similar parts throughout, Figure 1 is a plan view of the ii ed mold. Fig. 2 is a side view showing heating means applied to the mold inches long, 7 inches wide and 1 inch thick.

Iron strips 3, 4, a and 6 about inch square in cross section, are placed around the edges of the zinc to serve as sides of the mold.

Heat is next applied by any appropriate means, conveniently one or more gas burners 7, as shown, until the zinc melts. The source of heat is then shut off and the zinc allowed to cool down and solidify. I have also found that cooling can be hastened somewhat by directing an air blast'on the zinc after it has solidified, Without detriment. Here again, I have no data to give in regard to the rate of cooling but I direct an air blast on the bottom of the iron plate of the mold, from a inch gas cock in a pipe or hose containing air at 20 pounds gage pressure. This can be directed on the plate as soon as theheat is turned off, without detrimental effect.

Instead of melting rolled zinc in a mold, as given above by way of example, I may also melt ordinary cast zinc or zinc ingots, or hot molten zinc, may be poured into the heated mold and allowed to cool, as the essence of the invention is in the relatively slow cooling of the zinc. In ordinary diecasting, the mold heats up to some extent on account of the heat absorbed from the zinc, but it is relatively cool as compared with the heated mold inthis invention, since such mold is heated up to the melting point of zinc. It is not necessary to have the mold heated exactly to the temperature of molten zinc in case molten zinc is poured into it; but it mustbe heated much higher than the temperature of the mold in ordinary zinc casting.

When electrodes are made of the zinc cast in accordance with the preceding process, the zinc and its impurities function somewhat difierently when used in a battery, so

that much less mercury is required toamalgamate the electrodes. I have found that in most cases only about ii; the usual amount of mercury is necessary 'to properly amalga- 5 mate the new form of zinc electrodes, as determined by their performance in the bat ter cell.

; lXith the new zinc electrodes, impurities, such as lead and cadmium, are much less liable to scale or flake oil and short circuit the cell, or to coat over with incrustations as do ordinary rolled or cast zincs. Both of these characteristics. materially increase the life of the cell by permitting more of the zinc to be dissolved and by keeping the volt-v age up for a longer time than would be the case if the regular form of zinc were used.

Having described my invention, what I claim is p The process of making a zinc battery. electrode which consists in forming it into shape in a mold heated to substantially the melting temperature of zinc, and cooling the mold so that the zinc is solidified slowly.

In testimony whereof, I hereunto aflix my signature.

HARRY F. FRENCH. 

